Type C soil that is 20 feet or less in depth needs to have a maximum allowable slope of what?

Type C soil that is 20 feet or less in depth needs to have a maximum allowable slope of what?

• A. 1/2:1
• B. 1:1
• C. 1 1/2:1
• D. 2:1

Answer: (C)

In excavations, soil type and depth determine how steep the sides can safely be. Type C soil is the least stable, so the slope must be kept relatively gentle to prevent collapses. For a Type C excavation that is 20 feet or less, the steepest slope you’re allowed to use is 1.5 horizontal feet for every 1 vertical foot (written as 1.5:1). This provides a balance between practicality and safety for the weakest soil at this shallow depth. A wall that’s steeper than that—such as 1:1 or even more vertical—would be unsafe for Type C at this depth. A wall that’s shallower than 1.5:1, like 2:1, would also be acceptable, but it isn’t the maximum slope permitted. So the maximum allowable slope is 1.5:1.

In excavations, soil type and depth determine how steep the sides can safely be. Type C soil is the least stable, so the slope must be kept relatively gentle to prevent collapses. For a Type C excavation that is 20 feet or less, the steepest slope you’re allowed to use is 1.5 horizontal feet for every 1 vertical foot (written as 1.5:1). This provides a balance between practicality and safety for the weakest soil at this shallow depth. A wall that’s steeper than that—such as 1:1 or even more vertical—would be unsafe for Type C at this depth. A wall that’s shallower than 1.5:1, like 2:1, would also be acceptable, but it isn’t the maximum slope permitted. So the maximum allowable slope is 1.5:1.